Press-fit power module and related methods

ABSTRACT

Implementations of semiconductor packages may include: one or more die electrically coupled to a lead frame. The lead frame may be included within a housing. The semiconductor package may also include a set of signal leads extending from the housing, a set of power leads extending from the housing, and a plurality of press fit pins each fixedly coupled to the set of signal leads and the set of power leads. The set of signal leads and the set of power leads may be configured to couple with a substrate.

BACKGROUND 1. Technical Field

Aspects of this document relate generally to semiconductor packages,such as power modules for home appliances, the automotive industry, andindustrial applications.

2. Background

Conventionally, to couple semiconductor packages to substrates such asprinted circuit boards, the leads are soldered to the substrates. Otherdesigns include leads having a press fit pin structure at the terminalend of the leads.

SUMMARY

Implementations of semiconductor packages may include: one or more dieelectrically coupled to a lead frame. The lead frame may be includedwithin a housing. The semiconductor package may also include a set ofsignal leads extending from the housing, a set of power leads extendingfrom the housing, and a plurality of press fit pins each fixedly coupledto the set of signal leads and the set of power leads. The set of signalleads and the set of power leads may be configured to couple with asubstrate.

Implementations of semiconductor packages may include one, all, or anyof the following:

The one or more die electrically coupled to a lead frame may be a powermodule.

The press fit pins may be coupled to the signal leads and the powerleads through welding, soldering, or brazing.

The set of signal leads may be on a first side of the housing and theset of power leads may be on a second side of the housing opposite thefirst side.

The substrate may be a printed circuit board.

The plurality of press fit pins may include copper.

Implementations of semiconductor packages may include: a power modulehaving a set of signal leads coupled to the power module; a set of powerleads coupled to the power module on a side of the power module opposingthe set of signal leads; and a press fit pin welded, soldered, or brazedto each of the signal leads and to each of the power leads. The pressfit pin may be configured to couple with a circuit board.

Implementations of semiconductor packages may include one, all, or anyof the following:

The power module may include one of a switch, a rectifier, or aninverter.

The press fit pin may be coupled to one of the set of signal leads andto one of the set of power leads through welding, soldering, or brazingusing a jig.

The power module may further include a leadframe having the set ofsignal leads and the set of power leads.

The leadframe may include 99.9% purity copper.

The plurality of press fit pins may include a CuCrAgFeTiSi alloy.

Implementations of a method of manufacturing semiconductor packages mayinclude: providing a power module having a set of signal leads on afirst side and a set of power leads on a second side. The method mayalso include trimming a length of the set of signal leads and a lengthof the set of power leads and welding, soldering, or brazing a press fitpin of a plurality of press fit pins to each of the signal leads and toeach of the power leads. The method may also include bending the set ofsignal leads and the set of power leads to a desired angle configured tocouple with a substrate.

Implementations of a method of manufacturing semiconductor packages mayinclude one, all, or any of the following:

The plurality of press fit pins may be singulated press fit pins.

The method may further include coupling, prior to welding, soldering, orbrazing each press fit pin into a jig, a portion of each signal lead ofthe set of signal leads into the jig, and a portion of each power leadof the set of power leads into the jig.

The plurality of press fit pins may be framed press fit pins.

The method may further include singulating the plurality of press fitpins from a frame after welding, soldering, or brazing.

The welding, soldering, or brazing may further include one of ultrasonicwelding, soldering, or brazing and laser welding, soldering, or brazing.

The method may further include coupling a lead supporter to the set ofsignal leads and the set of power leads and to the power module, whereinthe lead supporter is configured to prevent deformation of the set ofsignal leads and the set of power leads.

The leadframe may include 99.9% purity copper and the press fit pins mayinclude a CuCrAgFeTiSi alloy.

The foregoing and other aspects, features, and advantages will beapparent to those artisans of ordinary skill in the art from theDESCRIPTION and DRAWINGS, and from the CLAIMS.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations will hereinafter be described in conjunction with theappended drawings, where like designations denote like elements, and:

FIG. 1 is a side view of an implementation of a semiconductor packagecoupled with a printed circuit board (PCB);

FIG. 2A is a top view of a power module having trimmed leads;

FIG. 2B is a top view of a power module having press fit pins coupled tothe trimmed leads;

FIG. 2C is top view of a power module having the leads bent;

FIG. 2D is a side view of an implementation of a semiconductor packagehaving the trimmed leads bent;

FIG. 2E is a side view of an implementation of a semiconductor packagecoupled with a printed circuit board (PCB);

FIG. 3 illustrates an implementation of method of coupling singulatedpress fit pins to trimmed leads of a power module;

FIG. 4 is another implementation of a method of coupling frame typepress fit pins to trimmed leads of a power module;

FIG. 5 is an implementation of a press-fit pin coupled in a welding jig;and

FIG. 6 is an implementation of a semiconductor package coupled with apress-fit insertion supporter pocket.

DESCRIPTION

This disclosure, its aspects and implementations, are not limited to thespecific components, assembly procedures or method elements disclosedherein. Many additional components, assembly procedures and/or methodelements known in the art consistent with the intended semiconductorpackages will become apparent for use with particular implementationsfrom this disclosure. Accordingly, for example, although particularimplementations are disclosed, such implementations and implementingcomponents may comprise any shape, size, style, type, model, version,measurement, concentration, material, quantity, method element, step,and/or the like as is known in the art for such semiconductor packages,and implementing components and methods, consistent with the intendedoperation and methods.

Referring to FIG. 1, an implementation of a semiconductor package 2coupled with a printed circuit board (PCB) 4 is illustrated. Asillustrated, the semiconductor package 2 includes a power module 6having a set of signal leads 8 coupled to the power module 6 on oneside. The power module may include, by non-limiting example, one of aswitch, a rectifier, or an inverter. The set of signal leads 8 arecoupled to the PCB through press fit pins 10 that couple into openingsformed into the printed circuit board. These openings may be drilled orotherwise formed vias through the PCB in particular implementations.However, in other implementations, the press fit pins 10 may couple intopin receivers formed on the PCB or coupled thereto via welding,soldering, or brazing.

On a side of the power module 6 opposing the set of signal leads 8 a setof power leads 12 are coupled to the power module 6. The power leads 12are coupled to the PCB through press fit pins 14. In variousimplementations, the press fit pins 14 may be coupled to the PCB throughopenings in the PCB or through pin receivers like any disclosed herein.Press fits pins 10 and 14 are welded, soldered, or brazed to the signalleads 8 and the power leads 12, respectively. In particularimplementations, the press fit pins 10, 14 are welded (or soldered, orbrazed) to the ends of the signal leads 8 and power leads 12,respectively, leads using a jig or guide. In various implementations,the leads 8 and 12 are made from high purity material for thermal andelectrical performance and the press-fit pins are made from a differentmaterial better adapted for bonding performance than the material of theleads.

While the power module 6 illustrated in FIG. 1 has both leads 8 andpower leads 12, in particular implementations, only one set of leads maybe used, either the leads 8 or the power leads 12. In someimplementations, the leads 8 may be distributed on both opposing sidesof the power module; in others the power leads 12 may be distributed onboth opposing sides of the power module. In other implementations, theleads 8 may be distributed on adjacent sides of the power module; inothers the power leads 12 may be distributed on adjacent sides of thepower module. In yet other implementations, the leads 8 may bedistributed on more than two sides of the power module; and in othersthe power leads may be distributed on more than two sides of the powermodule.

The material of the press-fit pins may have certain properties in orderto allow the press-fit pins to withstand the forces of insertion andextraction of the press-fit pins to substrates. In some implementations,the press-fit pins may be made from a CuCrAgFeTiSi alloy marketed underthe tradename K88 by Wieland-Werk, AG of Ulm, Germany. In suchimplementations, the material may be selected because of its desiredyield strength in combination with its electrical conductivity and goodstress relaxation resistance. Various other metal alloy materials may beemployed for use as the press-fit pins based on consideration of thesethree material properties of the alloy. In various implementations, thepress-fit pins may be formed of tin, nickel, other copper tin alloyssuch as CuSn₄, CuSn₆, CuNiSi, or other suitable materials having thedesired yield strength and electrical conductivity. The structure ofimplementations of semiconductor packages as described herein maydecrease co-planarity problems seen in other semiconductor packages.Press-fit pin insertion may be a fast, inexpensive, and reliablemanufacturing process that allows repair of a press-fit pin up to twotimes in a device. In this way, since the press-fit pins can berepaired, the power module can be reused beyond the lifetime of anyparticular press-fit pin.

In various implementations, the power module includes one or more dieelectrically coupled to a leadframe. The leadframe may be includedwithin a housing. The leadframe may, by non-limiting example, be made of99.9% purity copper (or higher than 99% copper), though in variousimplementations other purities of copper (more or less pure) or othermetals may be used, such as, by non-limiting example, silver, gold,aluminum, any combination thereof, and any other electrically conductivemetal. In various implementations, where the leadframe includes 99.9% orhigher purity copper, the copper material may be unsuitable for use as apress fit pin because it may deform/bend too much to successfullyfunction as a press fit pin. As previously described, press fit pins maybe coupled with either or both the signal set of leads and the powerleads. In various implementations, the press fit pins may be coupled tothe leads through, by non-limiting example, welding, soldering, brazing,laser welding, ultrasonic welding, thermal welding, laser soldering,laser brazing, ultrasonic soldering, ultrasonic brazing, or any othersuitable for coupling the metals of the leads to the press fit pinswhile preserving electrical conductivity. In various implementations ofsemiconductor packages as described herein the press fit pins are notintegrated into the original structure of the lead frame as in othersemiconductor packages but are separately coupled with the leads in asubsequent process. By non-limiting example, the press-fit pins may be,by non-limiting example, a solid pin having a solid press-in zone, acompliant pin having an elastic press-in zone, or any other type ofstructure designed to function like a press fit pin. Compliant pins aredesigned to deform during insertion and sustain a permanent contactnormal force when inserted into a reliable electrical and mechanicalconnection such as a PCB.

In various implementations, the semiconductor package may include a widevariety of other electrical components, including, by non-limitingexample, coils, capacitors, actuators, sensors, active electricalcomponents, passive electrical components, any combination thereof, andany other electrically operated and/or electrically conductive structureor device that can fit within the housing of the semiconductor package.By non-limiting example, power modules with having housings like thosedisclosed herein may be anti-lock braking (ABS) modules, electronicstability control (ESC) modules, sensor modules, antitheft antennae,antitheft modules, power distribution modules, power conversion modules,power regulation modules, and any other discrete device capable of beingplaced in a housing. The use of press-fit pins in these applications maymake the assembly process of the application easier and more reliable.

Referring to FIGS. 2A-2E, the configuration of a package at or aftervarious steps in an implementation of a method for manufacturingsemiconductor packages is illustrated. Referring to FIG. 2A, the a powermodule 16 having a set of signal leads 18 on a first side of the powermodule and a set of power leads 20 on a second side of the power moduleis illustrated. The method includes trimming the lengths of the signalleads 18 and the lengths of the power leads 20. The leads may be trimmedusing, by non-limiting example, a lead cutting machine, cutters, pliers,or other suitable equipment for trimming leads. As shown in FIG. 2B, thepower module 16 is illustrated following welding (or soldering orbrazing) a press fit pin of a plurality of press fit pins 22 to eachlead of the signal leads of the power module 26. The process of welding(or soldering or brazing) may be any disclosed in this document. A pressfit pin of a plurality of press fit pins 30 may also be welded to eachof the power leads 30 of the power module 26 in various implementationsof the method. As previously discussed, the process of welding (orsoldering or brazing) the press fit pins depends on the location of theparticular leads on the package. The process illustrated in FIGS. 2A-2Eillustrates the process where the plurality of leads 18 and power leads20 are on opposing sides. In implementations where there are only leadsor power leads, the method includes welding (or soldering or brazing)press fit pins on only the leads that are present. In implementationswhere the leads are on adjacent sides or more than one side, the processof welding may take place through multiple steps, the press fit pins onone side at a time, or on multiple sides at a time. In someimplementations, the press fit pins may not be welded simultaneously ona single side; rather one or more may be welded and the rest welded inone or more additional welding steps.

In various implementations, the plurality of press fit pins may besingulated press fit pins. In other implementations, the plurality ofpress fit pins may be framed press fit pins. Prior to welding (orsoldering or brazing), the method may further include coupling one, all,or any of the press fit pins into a jig. In particular implementations,the method may include coupling a portion of each single lead of the setof signal leads into the jig. In various implementations the method mayinclude coupling a portion of each power lead of the set of power leadsinto the jig. In some method implementations, both the signal leads andthe power leads may be coupled with a jig for welding, soldering, orbrazing. Welding support structures similar to those illustrated inFIGS. 5 and 6 may be used in various implementations.

Referring to FIGS. 2C and 2D, the method may include bending the set ofsignal leads 32 and the set of power leads 34 to a desired angleconfigured to couple with a substrate such as a PCB. Referring to FIG.2E, the method may further include coupling the semiconductor package 36to a substrate 38 through the press fit pins 40. The substrate mayinclude a PCB made from suitable materials such as fire retardant 4(FR-4) glass epoxy, fire retardant 5 (FR-5), and Bismaleimide-Triazine(BT) resin, or direct bonded copper (DBC). In various implementations,the method may further include coupling a lead supporter to the set ofsignal leads and the set of power leads. The lead supporter may beconfigured to prevent deformation of the set of signal leads and the setof power leads during transport and/or during insertion.

In various implementations, molded power modules having signal leads onone side of the power module and having power leads on the opposite sideof the power module may be placed into the X-axis of a positioningguider jig. The signal leads and power leads may be trimmed to apredetermined length before being placed into the guider jig. A set ofpress fit pins may also be placed into the guider jig in a Y-axisposition. In some implementations, the press-fit pins may be singulatedpress-fit pins. In other implementations, the press-fit pins may beframe type press-fit pins. The press-fit pins and the leads of the powermodule may be coupled through welding, soldering, or brazing. In variousimplementations, the welded press-fit signal leads and welded press-fitpower leads may be placed in a supporter pocket as illustrated in FIG. 6during insertion of the semiconductor package into a substrate such as aPCB. The welding/soldering/brazing of the leads with the press fit pinsmay provide a stronger and more reliable connection than seen inpackages using a click or insert coupling mechanism between the leadsand the press-fit pins. However, in some implementations, one, some, orall of the press fit pins may be coupled using a click or insertcoupling mechanism between the leads and the press-fit pins.

Referring to FIG. 3, another implementation of a method of manufacturingsemiconductor packages including a plurality of singulated press fitpins 42 is illustrated. A power module 44 having a set of signal leads46 and a set of power leads 48 is shown with the signal leads 46 and thepower leads 48 trimmed. The plurality of singulated press fit pins 42may be welded to the set of signal leads 46 and the set of power leads48 through various methods of welding, soldering, or brazing disclosedherein.

Referring to FIG. 4, another implementation of a method of manufacturingsemiconductor packages including a plurality of framed press fit pins 50is illustrated. A power module 52 having a set of signal leads 54 and aset of power leads 56 is illustrated with the signal leads 54 and thepower leads 56 trimmed. The plurality of framed press fit pins 50 may bewelded to the set of signal leads 54 and the set of power leads 54through welding, soldering, or brazing as previous described. The methodfurther includes singulating the press fit pins 50 from the frame afterthe press fit pins 50 have been welded to the leads 54 and 56 of thepower module 52.

Referring now to FIG. 5, a single press fit pin 58 in a welding,soldering, or brazing jig 60 is illustrated. The jig may help keep thepress fit pin coupled with the corresponding lead before and during thewelding process. Referring to FIG. 6, a plurality of press-fit pins 62supported by a press-fit insertion supporter pocket 64 is illustrated.The press-fit insertion supporter pocket 64 may be used to keep thepress fit pins 62 coupled with the leads 66 before and during thewelding process. In other implementations, the supporter pocket 64 mayalso be used to support the weld position between the leads 66 and thepress-fit pins 62 during insertion of the power module into a substrateand/or during transport of the power module.

The structure and method described herein may be applied to a variety ofapplications using press-fit pin connectivity including press-fit pinheaders, integrated housings or modules, or any other semiconductorpackages using a combination of leads and press-fit pins. Press-fit pinheaders specifically include an assembly of a plastic housing withcontact terminals. As described herein the terminals could be trimmedand the press-fit pins welded, soldered, or brazed to the end. Thiswould allow the terminals and press-fit pins to be made of differentmaterials without affecting the performance of the package or thepress-fit pins. Such technology may be used in home appliances, theautomotive industry, in industrial applications, or in otherapplications requiring high performance electronics with highreliability connections.

Use of press-fit pins on both the power leads and signal/signal leads invarious power module implementations like those disclosed herein mayhelp resolve solder crack issues for high power applications for powermodules. The method of manufacturing a semiconductor as described may beperformed on current equipment with minimal process change or machinemodification while maintaining if not increasing the performance of thesemiconductor packages.

In places where the description above refers to particularimplementations of semiconductor packages and implementing components,sub-components, methods and sub-methods, it should be readily apparentthat a number of modifications may be made without departing from thespirit thereof and that these implementations, implementing components,sub-components, methods and sub-methods may be applied to othersemiconductor packages.

What is claimed is:
 1. A semiconductor package comprising: one or moredie electrically coupled to a leadframe; the leadframe comprised withina housing; a set of signal leads extending from the housing; a set ofpower leads extending from the housing opposite the set of signal leads;and a plurality of press fit pins, each of the press fit pins welded,soldered, or brazed to the set of signal leads and the set of powerleads in a straight orientation; wherein the plurality of press fit pinsare configured to couple with a circuit board.
 2. The semiconductorpackage of claim 1, wherein the semiconductor package is a power module.3. The semiconductor package of claim 1, wherein the plurality of pressfit pins are coupled to the signal leads and the power leads througheither one of welding, soldering, or brazing using a jig.
 4. Thesemiconductor package of claim 1, wherein the set of signal leads are ona first side of the housing and the set of power leads are on a secondside of the housing opposing the first side.
 5. The semiconductorpackage of claim 1, wherein the leadframe comprises 99.9% purity copper.6. The semiconductor package of claim 1, wherein the plurality of pressfit pins comprise a CuCrAgFeTiSi alloy.
 7. A semiconductor packagecomprising: a power module comprising: a set of signal leads coupled tothe power module; a set of power leads coupled to the power module on aside of the power module opposing the set of signal leads; and a pressfit pin either one of welded, soldered, or brazed to each of the signalleads and to each of the power leads in a straight orientation; whereinthe press fit pin is configured to couple with a circuit board.
 8. Thesemiconductor package of claim 7, wherein the power module comprises oneof a switch, a rectifier, or an inverter.
 9. The semiconductor packageof claim 7, wherein the press fit pin is coupled to one of the set ofsignal leads and to one of the set of power leads through either one ofwelding, soldering, or brazing using a jig.
 10. The semiconductorpackage of claim 7, wherein the power module further comprises aleadframe comprising the set of signal leads and the set of power leads.11. The semiconductor package of claim 10, wherein the leadframecomprises 99.9% purity copper.
 12. The semiconductor package of claim 7,wherein the press fit pin comprises a CuCrAgFeTiSi alloy.
 13. Asemiconductor package comprising: one or more die electrically coupledto a leadframe; the leadframe comprised within a housing; a set ofsignal leads extending from the housing, wherein a first set ofpress-fit pins is coupled to an end of the set of signal leads; a set ofpower leads extending from the housing on the opposite side of thehousing from the set of signal leads, wherein a second set of press-fitpins is coupled to an end of the set of power leads; wherein the firstset press fit pins and the second set of press fit pins are configuredto couple with a circuit board.
 14. The semiconductor package of claim13, wherein the first set of press fit pins and the second set of pressfits pins are either one of welded, soldered, or brazed to the set ofsignal leads and the set of power leads, respectively.
 15. Thesemiconductor package of claim 13, further comprising a power module.16. The semiconductor package of claim 15, wherein the power modulecomprises one of a switch, a rectifier, or an inverter.
 17. Thesemiconductor package of claim 13, wherein the leadframe comprises 99.9%purity copper.
 18. The semiconductor package of claim 13, wherein thefirst set of press fit pins and the second set of press fit pins eachcomprise a CuCrAgFeTiSi alloy.